Photographic processes utilizing siloxane water spotting inhibitors



United States Patent 3,545,970 PHOTOGRAPHIC PROCESSES UTILIZING SILOX- ANE WATER SPOTTING INHIBITORS Edward J. Giorgianni, Peter J. Drago, .Ir., and Charles E. Groves, Rochester, N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey No Drawing. Filed Apr. 29, 1968, Ser. No. 725,147

Int. Cl. G03c 7/00 U.S. CI. 96-55 4 Claims ABSTRACT OF THE DISCLOSURE The treatment of hydrophilic colloids, e.g., gelatin, with alkoxypoly(ethyleneoxy)siloxanes containing from about to percent by weight silicon and/ or 57.5-72.5 percent by weight alkoxypoly(ethyleneoxy) groups, for example, in a final rinse for perforated color film, substantially inhibits water spotting.

This application relates to the treatment of water permeable hydrophilic colloids. In one aspect this invention relates to the processing of photographic elements. In another aspect this invention relates to the final rinse in the processing of photographic film. In still another aspect, this invention relates to the processing of perforated photographic film products, especially color film products, in which the final wet processing step desirably is a rinse in a solution consisting essentially of water and surfactant.

in wet processing of water permeable hydrophilic colloids, especially stratified colloids, it has been extremely difiicult to arrive at a processed product which is free from apparent surface defects. Such defects are very noticeable with photographic film products and occur most frequently with perforated film products, especially those having gelatin coatings thereon. The defects are most commonly attributed to a phenomenon called water spotting.

The problems associated with water spotting have recently become more acute in the strive to satisfy demands of the trade for decreased processing times and thereby decreased costs to both the tradesman and the consumer. In order to abbreviate the total time required for processing, utilization of higher temperatures in the various processing steps has been attempted with varying degrees of success. However, when increased temperatures are employed in the drying step, a significant and objectionable increase in water spotting is noted. Efforts to solve the problem through mechanical and chemical means heretofore have not resulted in a generally satisfactory solution to the water spotting problem. The mechanical variations employed, such as the use of air jets and/or mechanical vibrators, although reducing water spotting, often do not fit in presently utilized processing equipment and/or frequently add significantly to the cost. These factors severely limit the attractiveness of such modifications. Chemical variations that have been employed have not satisfactorily alleviated the water spotting problem and/or have contributed to contamination of the system resulting in emulsion fogging, processing scum, dye instability, corrosion, etc.

According to the present invention we have found methods and materials which will in addition to other advantages substantially prevent water spotting, even at high processing temperatures, and which are substantially free of the detrimental characteristics associated with analogous methods and materials. We have found that surface defects due to water spotting of water permeable hydrophilic colloids are substantially avoided by contacting the colloids with compositions containing a speci- -present invention are those siloxanes containing:

(1) one alkoxypoly(ethyleneoxy)siloxane group and (2) from 1 to 4 methyland/or ethyl-siloxane groups, advantageously those containing only:

(A) one group having the formula:

and

(B) from 1 to 4 groups having the formula:

(II R SiO 44) wherein:

(a) a has a value from 0 to 2 inclusive;

(b) b has a value from 2 to 3 inclusive;

(c) R is a methyl or an ethyl group;

(d) R is an alkyl group containing from 1 to 4 carbon atoms inclusive (i.e., a methyl, ethyl propyl, or butyl p);

(e) in has a value from 2 to 4 inclusive;

(f) n has an average value from about 4 to 14 inclusive;

(g) p has an average value from O to 5 inclusive;

(h) the ratio of n to p is at least 2 to 1;

(i) n-l-p has a value from about 4 to 17 inclusive (preferably from 4 to 12 inclusive);

(j) the alkoxypoly(ethyleneoxy) group is attached to the silicon atom of Formula I through at least two carbon atoms of the C H group; and

(k) the -C H (OC H (OC H OR group makes up from 57.5 to 72.5 average weight percent, advantageously -60 to 70 percent of the total structure or the total structure has an average silicon content of 10 to 15 weight percent, advantageously 11 to 14 percent.

These siloxanes are often mixtures whose average composition can be represented by Formulae I and II above, wherein n and p can have fractional values.

Three preferred classes of the siloxanes of this invenwherein q has an average value from about 4 to 12 inclusive, Me represents a methyl group, and the remaining symbols have the meanings defined above.

Specific siloxanes utilized in accordance with our invention are illustrated by those having the following for- Inulae:

These siloxanes are readily prepared by an addition reaction between a hydrosiloxane (i.e., a siloxane containing silicon-bonded hydrogen) and an alkenyl ether (e.g., a vinyl, allyl, or methallyl ether) of an alkoxy and hydroxy end-blocked poly(ethylene-oxide) as disclosed in the Bailey U.S. Pat. 3,299,112, filed June 19, 1964. The reaction conditions employed in addition reactions of this type are well known in the art and in general involve heating the reactants (e.g., at a temperature of from about 85 C. to 110 C.) in the presence of a platinum catalyst (e.g., chloroplatinic acid) and a solvent (e.g., toluene).

Siloxanes having the general formula:

wherein R is a lower alkyl, especially methyl or ethyl, are remarkably effective when utilized in accordance with our invention.

The advantages afforded by our invention are especially significant when aqueous solutions containing siloxanes having the Formula IX, wherein R is methyl, are utilized as a final rinse in the processing of gelatinous photographic products. Such rinse solutions are advantageously utilized as the final rinse in processing perforated gelatino-silver halide photographic film, for example, standard 35 mm. film, especially perforated color film wherein the process, e.g., as disclosed in U.S. Pats. 2,552,241 and 2,566,271, comprises:

(a) developing the film;

(b) stopping the development, e.g., by immersing the film in a stop bath;

(c) hardening the film;

(d) bleaching the film;

(e) fixing;

(f) rinsing in the final rinse; and

(g) placing the film in a drying environment.

Washing the film after one or more of steps (c), (d), and (e) is recommended.

When finally rinsing photographic film, it is sometimes desirable to include components other than water and the siloxane. For example, for some films a dye stabilizer is included in the rinse. Although the bath of the present invention may be used in such a manner, it is particularly well adapted to be utilized in a system and with a photographic film adapted for a final rinse consisting essentially of water and siloxane.

The siloxanes may be present in widely varying quantities, the specific concentration depending upon the particular siloxane chosen, the processing equipment, water hardness, and the element selected for processing. For photographic utility the concentration should be maintained at a sufiiciently low level to avoid a substantial carry-over in automated equipment where equipment is recycled, or in any processor where equipment might be contacted by siloxane and subsequently contacted by another processing solution, e.g., developer. If, for example, the carry-over to another processing solution results in a concentration of over 1 ml. siloxane per liter of solution, sensitometric changes are noted in some photographic products. Such a concentration does, however, represent an extremely large carry-over. The tolerance for such a large carry-over that the use of the specified siloxane affords is one of the outstanding advantages of the present invention. This advantage is magnified by the fact that it is generally desirable for final rinses in photographic processing to utilize concentrations of about .1 to about 5 ml. of siloxane per liter of solution (a weight ratio of about 1-500 parts siloxane to about 100,000 parts water). For some color photographic products, sensitometric changes are noted when the silicon concentration in rinse exceeds ml. per liter. It is especially desirable to utilize between about .5 to about 2 ml. polysiloxane per liter of solution (a weight ratio of about 1-4 parts siloxane to about 2,000 parts water).

Utilizing the final rinse bath according to the present invention results in processed film products substantially free from water spots and scum especially when utilized with well-known color systems, for example, as disclosed in Mannes et al. U.S. Pat. 2,252,718, wherein the photographic element comprising a support superposed with a red-sensitive silver-halide emulsion layer, a greensensitive silver-halide emulsion layer, a bleachable yellow filter layer, and a blue-sensitive silver-halide layer is image exposed and then processed. Color reversal processing involves a negative silver image development, washing, selective re-exposure of the bottom red-sensitive layer, cyan development of that layer with an alkaline solution containing a color developing agent and a cyanforming coupler, washing, selective re-exposure of the blue-sensitive layer with an alkaline solution containing a color developing agent, and a yellow-forming coupler, washing, fogging and magenta development of the greensensitive layer with an alkaline solution containing a color developing agent and a magenta-forming coupler, washing, followed by treatment with a potassium ferricyanide bleach bath, a sodium thiosulfate fix, washing and drying.

Products of remarkable quality are obtained when the final rinse according to the present inventon is utilized in lieu of a standard final rinse in processing standard multilayer photographic elements having the color-forming couplers incorporated in the silver halide emulsion layers as described in patents, such as Jelley and Vittum U.S. Pat. 2,322,027 issued June 15, 1943, Mannes et al. U.S. Pats. 2,304,939 and 2,304,940 issued Dec. 15, 1942, etc. Color processing of these elements, as is well known, usually involves the simultaneous color development of the three silver-halide emulsion layers with an alkaline solution containing a color developing agent, washing, hardening, washing, treatment with a potassium ferricyanide bleach bath, a sodium thiosulfate fix, washing and drying.

The following examples are intended to illustrate our invention and/or advantages thereof.

EXAMPLE 1 Two hundred 38 in. x 35 mm. strips of a standard perforated multilayer color film material having respectively superposed on a film support a red-sensitive layer containing cyan dye-forming couplers, a green-sensitive layer containing magenta dye-forming couplers, a bleachable yellow filter layer and a blue-sensitive layer containing yellow dye-forming couplers, which are exposed to a test pattern, are processed in accordance with general procedures on a 34 KO Pako Filmachine, a standard processing machine. Auxiliary heaters are supplied to raise the drying temperature to above 120 F. One hundred strips are processed utilizing a standard final rinse as disclosed in Henn et a1. U.S. Pat. 2,556,540 (a water solution containing surfactant and solvent). After drying under severe conditions these strips have a total of about 1,110 spots (11.1 per strip average) and contain streaks of processing scum. The other strips are processed in an identical manner except that the final rinse is an aqueous solution of 1.66 ml. siloxane (prepared in accordance with Example 1 of U.S. Pat. 3,299,112) per liter of water. After the same severe drying conditions these strips have a total of 10 spots (0.1 per strip). The latter 100 strips material show excellent dye stability characteristics. There is very little indication of processing scum and the film appears somewhat water repellant.

EXAMPLE 2 The procedure according to Example 1 is followed except that the siloxane solution contains about .5 ml. of the indicated siloxane per liter of water. Similar results are obtained.

EXAMPLE 3 The procedure according to Example 1 is followed except that the siloxane solution contains about 5.0 ml. of the indicated siloxane per liter of water. Similar results are obtained.

EXAMPLE 4 The procedure according to Example 1 is followed except that the siloxane solution contains 0.1 ml. of the indicated siloxane per liter of water. Similar results are obtained.

EXAMPLE 5 The procedure according to Example 5 is followed except that the siloxane composition has an average molecular weight of about 550-650 and a silicon content indicated to be about percent by weight (about percent by weight siloxy). Similar results are obtained.

EXAMPLE 7 The procedure according to Example 5 is followed except that the siloxane composition is indicated on elemental analysis to have a silicon content of about 9 percent (about 25 percent by weight siloxy). The siloxane composition when diluted with water as in Example 1 does not operate satisfactorily as a final rinse for photographic products having gelatin strata.

EXAMPLE 8 The procedure according to Example 5 is followed except that the siloxane composition is indicated on elemental analysis to be about 16 percent by weight silicon. Attempts to utilize this composition in a final rinse for gelatin-containing photographic products indicate the composition to be unsatisfactory.

EXAMPLE 9 A procedure according to Example 1 is followed except that the drying temperature is adjusted to 170 F. to provide a drying condition of increased severity. Thirty-two strips are tested, 8 in each of the indicated baths. The results are as follows:

Spots/ strip Tap water 87 Rinse solution described in US. 2,556,540 25 Siloxane of Example 1, 1.66 mL/liter 0' Siloxane of Example 1, .5 mL/liter 0 The films rinsed in solutions of our invention show reduced scum as compared to those rinsed in the other surfactant solution.

The compositions used in accordance with the present invention oifer additional advantages when compared to other surfactant solutions. The compositions used in accordance with the instant invention are, inter alia, relatively photographically inactive, of low toxicity, nonvolatile, difficult to ignite, noncorrosive, free from acidproducing chemicals, chemically inert, not subject to change by oxidation or' heat, and low foaming. In contrast to solutions of other surfactants, the solutions used according to our invention have decreased scumming characteristics as the concentration of siloxane is increased. Additionally, the specified siloxanes form true dispersions in water and thus will not settle out on standing.

The invention has been described in considerable detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. In a method for processing exposed photographic film comprising a transparent support having thereon at least one coating comprising water permeable hydrophilic colloid, said method comprising developing the film; bleaching the developed film; fixing the bleached film; rinsing the film; and drying the fihn: the improvement comprising rinsing said film in an aqueous solution comprising about .1 to about 5 ml. per liter of siloxane having (A) one alkoxypoly(ethyleneoxy)siloxane group and (B) from 1 to 4 methyl siloxane groups, a molecular weight of about 300 to about 1,000 and containing about 10 to about 15 weight percent silicon.

2. A method as in claim 1 wherein the siloxane has the general formula:

(OC2H4)t-m-O-R wherein R is methyl or ethyl.

3. In a method as in claim 1 for processing exposed, perforated photographic color film comprising a transparent support having coated thereon a plurality of superposed layers of gelatin, at least some of the layers containing incorporated color forming couplers, said method comprising:

(a) developing the film in a color developer solution;

(b) treating the developed film in a stop bath;

(c) contacting the film with a solution of a photographic hardener;

(d) washing the film;

(e) treating the film in a bleach bath;

(f) washing the bleached film;

(g) treating the film with a fixer;

(h) washing the fixed film;

(i) rinsing the film; and

(j) drying the film: the improvement comprising rinsing the film with an aqueous solution consisting essentially of about .5 to about 2 ml. per liter of a siloxane composition represented by the general formula:

4. In a method of processing exposed photographic film comprising a transparent support having thereon at least one coating comprising gelatin, said method comprising subjecting said film to a series of processing steps to develop and fix an image thereon, said method including steps of rinsing said film and then drying said film: the improvement comprising rinsing said film in an aqueous solution comprising about .1 to about 5 ml. per liter of a siloxane to prevent spotting on said film, said siloxane having the general formula of claim 2.

References Cited UNITED STATES PATENTS 2,556,540 6/1951 Henn et al. 96-50 3,299,112 l/ 1967 Bailey 260448.2U 3,369,896 2/ 1968 Selmann et a1 96-56 NORMAN G. TORCHIN, Primary Examiner W. H. LOUIE, JR., Assistant Examiner US. Cl. X.R. 96--50 Anestin Officer I.

g gy UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 545 ,970 Dated December 8 1970 Inventor(s) Edward J. Giorgianni, Peter J. Drage, Charles E.

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 2, line 59, change "p" to --q--. Col. 3, line 12, chang "(XI) to --(IX)-. Col. 6 in claim 3, change the bottom lin of the formula from "(6 CH CH -'OC3" to M Anew Id'nrd H. Member, It". 

